Booster pump



March 11, 1958 c. c. WRIGLEY 2,326,149

BOOSTER PUMP Filed March 23, 1955 3 Sheets-Sheet 1 .INVENTOR C. C. WRIGLEY BOOSTER PUMP March 11, 1958 Filed March 23. 1955 5 Sheets-Sheet 2 INVENTOR g/aim Wily/5y r 2,826,149 BOOSTERrPUMP Application March '23, 1955, Serial No. 496,164 7 Claims. (Cl. 1 03-51) This invention relates to booster pumps and more particularly concerns a pump of this type which is controlled by fluid pressure.

it is frequently desirable or necessary in hydraulic circuits, for example, to increase the available line pressure for the operation of one or more actuators, either not susceptible of operation at line pressure or giving better performance at a higher pressure. Thus, in an auto motive vehicle equipped with a hydraulic transmission, it is possible to draw'oil under substantial pressure from the transmission for operation of various accessories through suitable jacks, power cylinders, or the like. However, the pressure so derived is not generally adequate with respect to certain accessories as, for example, a hydraulic power steering system of the type comprising a closed-center valve and an accumulator from which the steering actuator or assist-or draws.

The invention herein answer-s fully to the indicated specific need and booster pumps according therewith are adapted for many other applications too numerous to mention.

Several of the more important objects of the invention are: to provide a booster pump capable of control by fluid pressure; to provide such a pump capable of control by fluid at inlet pressure; to provide a pump of simple design and low cost, which will be virtually infallible in operation.

Other objects and features of the invention will be apparent from the following description of a preferred embodiment thereof which will proceed with reference to the accompanying drawings in which:

Figure l is a schematic'representation of the particular P p;

Figure 2 is a plan showing the pump with the top cover removed;

Figure 3 is parts;

Figure 4 schematically illustrates a modified construction; and

Figure 5 is a performance curve on the pump of Figures 1-3.

Referring first to Figure l, the principal working parts of the pump are a motor piston having pumping pistons 12 connected thereto or integral therewith and a control valve spool 14-. This spool or plunger comprises lands 16, 18, 20, and 22 and an enlarged portion 24 of substantially the same diameter as the lands functional with relation to the springloa-ded balls 26. These balls and the associated springs afford a detent action for a purpose which will be shortly explained.

Spool 14 is reciprocal within a valve body formed to provide annular channels Fall, 32, 34, 36, 38, and 40. Also there is provided central exhaust channels 42 opening to a common exhaust line 44-.

Fluid at line pressure, 90425 p. s. i., for example, enters the pump via line 46. This line is common to lines 48 and 50, which connect, respectively, with the annular channels 32 and 38. Branching from line 4% a longitudinal section showing the principal tee l atent t) is aline 52 opening to the chamber 54, in which'the lefthand pumping piston 12 reciprocates, and connecting with the highpressure or discharge line'56. Similarly, line 58, branching from line 50 opens-to the chamber-60, in which the right-hand pumping piston 12 reciprooates, and terminates in the high pressure line 56. Each of lines 52 and 58 has thereina pair ofcheck valves 62, '64 and 6d, 68 respectively.

In addition ito-the lines or conduits just-described,the system includes lines or passageways 70 and 72 extending from the annular channels 34 and 36, respectivelyytothe chamber 74 in which the motor piston 10 reciprocates, line '70 serving the left-hand portion of such 'chamb'ertas delineated by-the piston), line 72 the right-hand portion thereof.

With the control valve spool 14 in the position shown, fluid at line pressure is entering the right-hand portion-of the chamber 74, moving the piston 10 leftward, through line 50, annular channels 38, 36, and line 72. Simultaneously, fluid at exhaust pressure is being discharged from the lefthand pontion of the chamber 74 via line 7 0, annular channels 34 and 42, and the common exhaust line 44. As the piston 10 completes its leftward stroke, line 76, which includes an orifice 78, and which connects with annular channel 40 at the right-hand end of the spool 14, becomes open to the pumping chamber 60. On this occurrence, fluid from such chamber enters the annular channel 40, there to exert a leftward force on the valve spool 14 to shift the same in that direction to an extent such that the balls 26 over-ride the center of the enlarged portion 24 of the valve spool. Once this overriding has taken place, the further leftward movement of the spool is effected by expansion of the springs backing up the balls.

A central bore 80, extending through the valve spool, connects with radial passageways 82 in the spool so that fluid is permitted to bleed from the annular channel or chamber 40 to exhaust.

As the valve spool 14 reaches its leftward position corresponding to the maximum leftward displacement of piston 10, it closes off the exhaust passageway from the left side of the chamber 74 so that the piston is locked in position. On further progress of the valve spool to the left, the feed to the right-hand portion of chamber 74 becomes closed off, with opening of the left-hand portion of the chamber to line pressure. Piston 10, however, does not yet begin its rightward stroke, because the righthand exhaust passageway is not yet open. On final leftward movement of the valve spool, with the force required for such movement being supplied by the detent means, annular channel 36 becomes open to the righthand exhaust channel 42 land the piston 10 accordingly moves rightward.

With completion of the rightward stroke of the piston, the valve action is reversed, the rightward movement of the spool being initiated by the fluid pressure developing in annular channel or chamber 30, this fluid being derived from the pumping chamber 54 through a line 84 having an orifice 86 therein and representing the counterpart of the line 76.

it should be evident that the reciprocation of the pistons 12 provides a pumping action resulting in the drawing of inlet fluid from lines 52 and 58 and the discharge of fluid into the common high pressure line 56. With the piston 10 in its position shown (Figure l), the right-hand pumping piston 12 is in the middle of its suction stroke, while the left-hand pump pistonis in the middle of its discharge stroke, a condition reflected by the ball check valves 64 and 66 both of which are shown off their seats.

In view of the foregoing, description is required in the case it is believed that little of Figures 2 and 3 assua e showing the actual pump construction and wherein the same numerals are employed as in Figure 1, the parts being reversed. It may be noted, however, that all of the moving parts are housed within a single block or body 38 of metal or other appropriate material, suitably bored and counterbored to provide the various passageways and chambers, Alternatively, the valve body may be cast to reduce the amount of boring necessary. The particular construction includes two cover plates 94 and 92 shown as bolted to the body $8.

In Figure 2, certain of the passageways and check valves are shown in broken lines as these would not actually appear in the true section.

Going now to Figure 4 illustrating a modified arrangement and wherein parts functionally similar or identical to parts shown in Figure 1 are denoted by like numerals, the numerals, however, being primed, it is to be noted that in this case the fluid at inlet pressure which initiates the reverse movement of the valve spool 14 is not derived from the lines 52 and 58 but from lines 94 and 96, respectively.

Line 94 opens to annular channel 32 which in turn is open to the inlet line 46. Similarly, line 96 connects with the annular channel 38' which in turn connects with the inlet line 46 via branch line 56). Transfer of inlet fluid from lines 94 to line 84', for example, occurs when the left-hand pumping piston 12' is in its position where the annular groove ltltl formed in the piston is in centered relation with respect to the lines 34 and 94, more accurately the orifice portions 86 and N2 of these lines.

With the parts in their relative positions as shown in Figure 4, the motor piston 10 is being moved to the left by inlet fluid entering the chamber '74 from line 72', line '7il being open to exhaust line 44. As the right-hand pumping piston 12' reaches a leftward position such that the corresponding annular groove 100 allows for fluid flow between the line 96 and the line 76 the valve spool 14' is shifted leftwardly as afore described to reverse the action, the initial movement of the spool being induced by the pressure of inlet fluid at 4d.

Further description of the modified construction represented by Figure 4 is believed unnecessary in view of the detailed description supplied above referring to Figure 1.

In the case of either construction illustrated, the pumping action will be fast when the high pressure discharge is being dissipated, as in the operation of an actuator, and when this pressure is relatively low. But as the high pressure approaches a certain maximum value, the pump will slow down and will maintain this maximum pressure with only enough movement to compensate for leakage of high pressure fluid. The curve of Figure 5 illustrates this characteristic of the pump. In such figure the discharge pressures are plotted as ordinates, the times, in seconds, required for the discharge of one quart of fluid (hydraulic transmission oil) at these pressures as abscissae. The figures were obtained from the operation of a pump conforming to Figures 13. The inlet pressure was 120 p. s. i., the exhaust pressure 15 p. s. i. This pump has a displacement of 0.33 cubic inches per cycle, equivalent to 153 cycles per quart discharged.

I claim:

1. A booster pump having fluid motor means actuable by the pressure of inlet fluid, pumping means operably connected to said fluid motor means, said pumping means being housed within a chamber connected to the source of inlet fluid, control means for said motor and pumping means including a housing confining a movable element, means governed by said pumping means to bring about initial movement of said movable element, and a detent device comprising yielo'a-ble means accommodated within said housin and means loaded by said yieldable means having an operable connection with said movable element including an override arrangement whereby a final increment of force is supplied in the displacement of said movable element.

2. A booster pump having double-acting fluid motor means actuable by the pressure of inlet fluid, pumping means operably connected to said fluid motor means, said pumping means being housed within a chamber connected to the source of inlet fluid, control means for said motor and pumping means including a housing confining a movable element displaceable in two directions, means governed by said pumping means to bring about initial movement of said movable element in either direction, and a detent device comprising yieidable means accommodated within said housing and further comprising means loaded by said yieldable means having an operable connection with said movable element including an override arrangement whereby a final increment of force is supplied in the displacement of said movable element in either direction.

3. A booster pump including a double-acting fluid motor having communication with a source of fluid pressure, means providing a pumping chamber at either end of said motor, said chambers being connected to a source of fluid, pumping means in each said chamber operably connected to said motor, control means for said motor and pumping means including a housing confining a movable element actuable by fluid pressure and displaceable in two directions, means providing a pair of chambers for receiving pressure fluid to bring about initial movement of said movable element in either direction, and a deter device comprising yieldable means accommodated within said housing and further comprising means loaded by said yieldable means having an operable connection with said movable element including an override arrangement whereby a final increment of force is supplied in the displacement of said movable element in either direction.

4. A booster pump including a double-acting fluid motor actuable by the pressure of inlet fluid, means providing a pumping chamber at either end of said motor, said chambers being connected to a source of fluid, pumping means in each said chamber operably connected to said motor, control means for said motor and pumping means including a housing confining a movable element actuable by fluid pressure and displaceable in two directions, means providing a pair of chambers for receiving inlet fluid valved by said pumping means to bring about initial movement of said movable element in either direction, and a detent device comprising yieldable means accommodated within said housing and further comprising means loaded by said yieldable means having an operable connection with said movable element including an override arrangement whereby a final increment of force is supplied in the displacement of said movable element in either direction.

5. A booster pump according to claim 4 where said detent device comprises a spring-loaded ball, the ball seating in annular grooves at the sides of a rounded landlike enlargement carried by said movable element.

6. A booster pump having fluid motor means actuable by the pressure of inlet fluid, pumping means operably connected to said fluid motor means, said pumping means being housed within a chamber connected to the source of inlet fluid, control means for said motor and pumping means including a housing confining a movable element, means providing a pair of chambers for receiving inlet fluid valved by said pumping means to bring about initial movement of said movable element, and a detent device comprising yieldable means accommodated within said housing and further comprising means loaded by said yieldable means having an operable connection with movable element including an override arrangement whereby a final increment of force is supplied in the displacement of said movable element.

7. A booster pump assembly including a fluid motor comprising a cylinder confining a double-acting piston, said cylinder having communication with a source of fluid pressure, means providing a pumping chamber at either end of said cylinder, each of said chambers having communication with said source and confining a plunger extending from a face of said piston, control means for said piston and plungers including a housing fixed to said cylinder and confining an axially movable element actuable by fluid pressure and displaceable in two directions, means providing a chamber at each end of said element for receiving fluid at inlet pressure valved by said plungers to bring about initial movement of said element in either direction, and a detent device comprising yieldable means accommodated Within said housing and further comprising means loaded by said yieldable means having an operable connection with said movable element including an override arrangement whereby a final increment of force is supplied in the displacement of said movable element in either direction.

References Cited in the file of this patent UNITED STATES PATENTS 

